Jenny Graves

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Jenny Graves

AC FAA
Born (1941-11-24) 24 November 1941 (age 82)
Adelaide, South Australia
Nationality Australian
Alma mater
Occupation Geneticist
Employer La Trobe University
Awards
Website biology.anu.edu.au/people/jennifer-graves

Jennifer Ann Marshall Graves AC FAA (born 24 November 1941) is an Australian geneticist. She is Distinguished Professor within the La Trobe Institute for Molecular Science, La Trobe University, Australia and Professor Emeritus of the Australian National University. [1]

Contents

Early life and education

Graves was born in Adelaide, South Australia in 1941. She was born as the first daughter to Tim Marshall – head of the Division of Soils at Commonwealth Scientific and Industrial Research Organisation (CSIRO) – and Ann Nicholls, who lectured at the Geography Department at the University of Adelaide. Her younger sister is Lyn Richards.

Graves attended Highgate Primary School, then Presbyterian Girls' College (now Seymour College), both in Adelaide. [2]

She received her BSc from the University of Adelaide in 1964, and an MSc in 1967 for work on the epigenetic silencing of one X chromosome in female marsupials. [3] She then received a PhD in 1971 for her work on the control of DNA synthesis from the University of California, Berkeley. [2]

Career

In 1971, Graves returned to Australia to lecture in genetics at La Trobe University, where she then became Professor in 1991. [2] As a teacher, she champions the idea that every biology topic is united by evolution and endorses the maxim that “Nothing in Biology Makes Sense Except in the Light of Evolution". [3]

Graves has published numerous high-profile papers in her career and has made a seminal contribution to understanding the organization, evolution, function and conservation of the mammalian genome. To do this, she has utilised the genetic diversity of Australian animals (specifically the kangaroo, platypus, Tasmanian devils and dragons (lizards)). Her work had led to significant and influential new theories on the origin and evolution of the human sex chromosomes and sex determination, including the controversial prediction that the human Y chromosome is disappearing. [4] She also made the critical discovery that the epigenetic silencing of mammalian X chromosomes occurs by transcriptional inhibition, and that this is mediated by DNA methylation. In the mid-1980s, Graves became involved in international comparative gene mapping and sequencing projects, where she promoted the value of including distantly related species in comparative genomics analyses and initiated projects to sequence the genomes of Australian marsupials and the platypus. In 2001 she became head of the Comparative Genomics Research Unit and Director of the ARC Centre for Excellence in Kangaroo Genomics, based at the Research School of Biological Sciences at the Australian National University. [3] During this time she worked extensively with Associate Professor Janine Deakin. [5]

In 1999 Graves was elected as Fellow of the Australian Academy of Science. Since this time she has served first as Foreign Secretary, then as Education Secretary where she was responsible for the Academy's science education projects. [6] [7] She is a 2006 L’Oreal-UNESCO Laureate, and has received many awards for her work, including the MacFarlane Burnet Medal for research in biology, and an Order of Australia. [8] [9] [2]

In 2011 Graves returned to Melbourne as Distinguished Professor at La Trobe University, but retains honorary positions at the Australian National University (Professor Emeritus), the University of Canberra (Thinker-in-Residence) and the University of Melbourne (Professorial Fellow). [3] [6] [7]

In 2017 she was awarded the Prime Minister's Prize for Science (Australia) for "her pioneering investigations of the genetics of sex". [10]

Sex Determination

Graves, in conjunction with her then PhD student Andrew Sinclair, was instrumental in providing evidence that the ZFY gene, at the time proposed to be the testis-determining factor, was not required for sex determination in mammals. Sex determination in placental mammals (including marsupials) results from a testis-determining gene on the Y chromosome. Via comparative genomics, Graves and Sinclair showed that ZFY is found on chromosome 5 in kangaroos and chromosome 3 in the fat-tailed dunnart rather than the Y chromosome, and therefore could not be involved in determining sex. [11] [12] Sinclair later showed that SRY was in fact the gene responsible for sex determination in mammals. [13] [12]

Following this, Graves discovered that the platypus sex chromosomes are homologous to the bird ZW rather than conserved with the mammalian XY. Owing to this work, the emergence of mammalian sex chromosomes could be dated back to between 160-190 million years ago, between the divergence of therian mammals from monotremes and the divergence of the marsupial-eutherian species. [12]

Graves' work on sex determination led to the discovery that the Australian reptile the dragon lizard exhibits both genetic and temperature dependent sex determination. At normal temperatures, the sex of offspring is determined via genetic factors (ZZ male, ZY female) as two copies of this Z-borne gene (ZZ) are required to induce testis formation. At higher temperatures, however, all hatchlings are female. It is proposed that this occurs due to heat inactivation of a dose sensitive Z-borne gene, resulting in ZZ hatchlings with insufficient sex determination product. Due to this reduced dose, ZZ hatchlings develop into sex-reversed females. [14] [15] This work condradicted the prevailing hypothesis at the time that genetic and temperature dependent sex determining systems were fundamentally different.

Honours

Related Research Articles

Genomic imprinting is an epigenetic phenomenon that causes genes to be expressed or not, depending on whether they are inherited from the mother or the father. Genes can also be partially imprinted. Partial imprinting occurs when alleles from both parents are differently expressed rather than complete expression and complete suppression of one parent's allele. Forms of genomic imprinting have been demonstrated in fungi, plants and animals. In 2014, there were about 150 imprinted genes known in mice and about half that in humans. As of 2019, 260 imprinted genes have been reported in mice and 228 in humans.

<span class="mw-page-title-main">XY sex-determination system</span> Method of determining sex

The XY sex-determination system is a sex-determination system used to classify many mammals, including humans, some insects (Drosophila), some snakes, some fish (guppies), and some plants. In this system, the sex of an individual is determined by a pair of sex chromosomes. In most cases, females have two of the same kind of sex chromosome (XX), and are called the homogametic sex. Males have two different kinds of sex chromosomes (XY), and are called the heterogametic sex.

<span class="mw-page-title-main">Sex-determination system</span> Biological system that determines the development of organisms sex

A sex-determination system is a biological system that determines the development of sexual characteristics in an organism. Most organisms that create their offspring using sexual reproduction have two common sexes and a few less common intersex variations.

<span class="mw-page-title-main">Y chromosome</span> Sex chromosome in the XY sex-determination system

The Y chromosome is one of two sex chromosomes in therian mammals and other organisms. Along with the X chromosome, it is part of the XY sex-determination system, in which the Y is the sex-determining because it is the presence or absence of Y chromosome that determines the male or female sex of offspring produced in sexual reproduction. In mammals, the Y chromosome contains the SRY gene, which triggers development of male gonads. The Y chromosome is passed only from male parents to male offspring.

<span class="mw-page-title-main">Haldane's rule</span> Observation in evolutionary biology

Haldane's rule is an observation about the early stage of speciation, formulated in 1922 by the British evolutionary biologist J. B. S. Haldane, that states that if — in a species hybrid — only one sex is inviable or sterile, that sex is more likely to be the heterogametic sex. The heterogametic sex is the one with two different sex chromosomes; in therian mammals, for example, this is the male.

David C. Page is an American biologist and professor at the Massachusetts Institute of Technology (MIT), the director of the Whitehead Institute, and a Howard Hughes Medical Institute (HHMI) investigator. He is best known for his work on mapping the Y-chromosome and on its evolution in mammals and expression during development. He was cited by Bryan Sykes in Adam's Curse: A Future Without Men.

<span class="mw-page-title-main">Sex-determining region Y protein</span> Protein that initiates male sex determination in therian mammals

Sex-determining region Y protein (SRY), or testis-determining factor (TDF), is a DNA-binding protein encoded by the SRY gene that is responsible for the initiation of male sex determination in therian mammals. SRY is an intronless sex-determining gene on the Y chromosome. Mutations in this gene lead to a range of disorders of sex development with varying effects on an individual's phenotype and genotype.

<span class="mw-page-title-main">Sex-chromosome dosage compensation</span>

Dosage compensation is the process by which organisms equalize the expression of genes between members of different biological sexes. Across species, different sexes are often characterized by different types and numbers of sex chromosomes. In order to neutralize the large difference in gene dosage produced by differing numbers of sex chromosomes among the sexes, various evolutionary branches have acquired various methods to equalize gene expression among the sexes. Because sex chromosomes contain different numbers of genes, different species of organisms have developed different mechanisms to cope with this inequality. Replicating the actual gene is impossible; thus organisms instead equalize the expression from each gene. For example, in humans, female (XX) cells randomly silence the transcription of one X chromosome, and transcribe all information from the other, expressed X chromosome. Thus, human females have the same number of expressed X-linked genes per cell as do human males (XY), both sexes having essentially one X chromosome per cell, from which to transcribe and express genes.

<span class="mw-page-title-main">ZW sex-determination system</span> Chromosomal system

The ZW sex-determination system is a chromosomal system that determines the sex of offspring in birds, some fish and crustaceans such as the giant river prawn, some insects, the schistosome family of flatworms, and some reptiles, e.g. majority of snakes, lacertid lizards and monitors, including Komodo dragons. It is also present in some plants, where it has probably evolved independently on several occasions. The letters Z and W are used to distinguish this system from the XY sex-determination system. In the ZW system, females have a pair of dissimilar ZW chromosomes, and males have two similar ZZ chromosomes.

Barbara J. Meyer is a biologist and genetist, noted for her pioneering research on lambda phage, a virus that infects bacteria; discovery of the master control gene involved in sex determination; and studies of gene regulation, particularly dosage compensation. Meyer's work has revealed mechanisms of sex determination and dosage compensation—that balance X-chromosome gene expression between the sexes in Caenorhabditis elegans that continue to serve as the foundation of diverse areas of study on chromosome structure and function today.

Ohno's law was proposed by a Japanese-American biologist Susumu Ohno, saying that the gene content of the mammalian species has been conserved over species not only in the DNA content but also in the genes themselves. That is, nearly all mammalian species have conserved the X chromosome from their primordial X chromosome of a common ancestor.

<span class="mw-page-title-main">Female</span> Sex of an organism that produces ova

An organism's sex is female if it produces the ovum, the type of gamete that fuses with the male gamete during sexual reproduction.

<span class="mw-page-title-main">Monotreme</span> Order of egg-laying mammals

Monotremes are mammals of the order Monotremata. They are the only group of living mammals that lay eggs, rather than bearing live young. The extant monotreme species are the platypus and the four species of echidnas. Monotremes are typified by structural differences in their brains, jaws, digestive tract, reproductive tract, and other body parts, compared to the more common mammalian types. Although they are different from almost all mammals in that they lay eggs, like all mammals, the female monotremes nurse their young with milk.

<span class="mw-page-title-main">Stephen J. O'Brien</span> American geneticist

Stephen J. O'Brien is an American geneticist. He is known for his research contributions in comparative genomics, virology, genetic epidemiology, mammalian systematics and species conservation. Member of the National Academy of Sciences and a Foreign Member of the Russian Academy of Sciences. Author or co-author of over 850 scientific articles and the editor of fourteen volumes.

<span class="mw-page-title-main">Microchromosome</span> Type of chromosome

A microchromosome is a chromosome defined for its relatively small size. They are typical components of the karyotype of birds, some reptiles, fish, amphibians, and monotremes. As many bird genomes have chromosomes of widely different lengths, the name was meant to distinguish them from the comparatively large macrochromosomes. The distinction referred to the measured size of the chromosome while staining for karyotype, and while there is not a strict definition, chromosomes resembling the large chromosomes of mammals were called macrochromosomes, while the much smaller ones of less than around 0.5 µm were called microchromosomes. In terms of base pairs, by convention, those of less than 20Mb were called microchromosomes, those between 20 and 40 Mb are classified as intermediate chromosomes, and those larger than 40Mb are macrochromosomes. By this definition, all normal chromosomes in organisms with relatively small genomes would be considered microchromosomes.

<span class="mw-page-title-main">Mammalian reproduction</span> Most mammals are viviparous, giving birth to live young

Most mammals are viviparous, giving birth to live young. However, the five species of monotreme, the platypuses and the echidnas, lay eggs. The monotremes have a sex determination system different from that of most other mammals. In particular, the sex chromosomes of a platypus are more like those of a chicken than those of a therian mammal.

Janine Deakin is a professor at the University of Canberra and Executive Dean of the Faculty of Science and Technology. She is a geneticist with expertise in the areas of comparative genomics, epigenetics, genetic immunology and genome structure and regulation. A majority of her work has focused on the Australian marsupials and monotremes where her cytogenetic and molecular research on marsupial chromosomes and development of strategies to map genomes has provided important insight into the evolution of mammalian genomes.

<span class="mw-page-title-main">Katherine Belov</span> Australian geneticist

Katherine Belov is an Australian geneticist, professor of comparative genomics in the School of Life and Environmental Sciences and Pro Vice Chancellor of Global Engagement at the University of Sydney. She is head of the Australasian Wildlife Genomics Group and research expert in the area of comparative genomics and immunogenetics, including Tasmanian devils and koalas, two iconic Australian species that are threatened by disease processes. Throughout her career, she has disproved the idea that marsupial immune system is primitive, characterized the South American gray short-tailed opossum's immune genes, participated in the Platypus Genome Project, led research identifying the properties of platypus venom, and identified the cause of the spread of the Tasmanian devil's contagious cancer.

Peter Anthony Koopman is an Australian biologist best known for his role in the discovery and study of the mammalian Y-chromosomal sex-determining gene, Sry.

<span class="mw-page-title-main">Evolution of sex-determining mechanisms</span>

The evolution of sex-determining mechanisms, characterized by the evolutionary transition to genetic sex determination or temperature-dependent sex determination from the opposite mechanism, has frequently and readily occurred among multiple taxa across a transitionary continuum.

References

  1. ↑ "Professor Jennifer Graves". ANU College of Medicine, Biology & Environment: Research School of Biology. Archived from the original on 2 February 2014. Retrieved 19 January 2014.
  2. 1 2 3 4 "Interviews with Australian scientists - Professor Jenny Graves". Australian Academy of Science. Archived from the original on 29 October 2013. Retrieved 28 October 2013.
  3. 1 2 3 4 "Staff profile, Science, Technology and Engineering, La Trobe University". 22 February 2014. Archived from the original on 22 February 2014. Retrieved 29 July 2019.
  4. ↑ Thursday, 23 February 2012 ABC/AFP (23 February 2012). "Many years of life left in Y chromosome". www.abc.net.au. Retrieved 29 July 2019.{{cite web}}: CS1 maint: numeric names: authors list (link)
  5. ↑ "Ms Janine Deakin - Researchers - ANU". 19 August 2014. Archived from the original on 19 August 2014. Retrieved 29 July 2019.
  6. 1 2 Director (Research Services Division). "Emeritus Professor Jennifer Graves". researchers.anu.edu.au. Retrieved 29 July 2019.
  7. 1 2 Holmes, David (1 October 2014). "Jenny Graves: the free spirit of scientific enquiry". The Lancet Diabetes & Endocrinology. 2 (10): 779. doi: 10.1016/S2213-8587(14)70116-0 . ISSN   2213-8587. PMID   25127484.
  8. 1 2 "Macfarlane Burnet Medal and Lecture". Australian Academy of Science. Retrieved 22 February 2017.
  9. 1 2 "Staff profile: Professor Jenny Marshall Graves AO, FAA". La Trobe University. Archived from the original on 22 February 2014. Retrieved 22 January 2014.
  10. 1 2 "Scientist who predicts male sex chromosome is declining takes PM's prize". ABC News. 18 October 2017. Retrieved 18 October 2017.
  11. ↑ Sinclair, Andrew H.; Foster, Jamie W.; Spencer, James A.; Page, David C.; Palmer, Mark; Goodfellow, Peter N.; Graves, Jennifer A. Marshall (December 1988). "Sequences homologous to ZFY, a candidate human sex-determining gene, are autosomal in marsupials". Nature. 336 (6201): 780–783. Bibcode:1988Natur.336..780S. doi:10.1038/336780a0. ISSN   0028-0836. PMID   3144651. S2CID   4345322.
  12. 1 2 3 Graves, Jennifer A. Marshall (23 January 2017). "How Australian mammals contributed to our understanding of sex determination and sex chromosomes". Australian Journal of Zoology. 64 (4): 267–276. doi: 10.1071/ZO16054 . ISSN   1446-5698.
  13. ↑ Gitschier, Jane (27 June 2008). "The Exception That Proves the Rule: An Interview with Jenny Graves". PLOS Genetics. 4 (6): e1000063. doi: 10.1371/journal.pgen.1000063 . ISSN   1553-7404. PMC   2377341 . PMID   18584021.
  14. ↑ Graves, Jennifer A. Marshall (2008). "Weird Animal Genomes and the Evolution of Vertebrate Sex and Sex Chromosomes". Annual Review of Genetics. 42 (1): 565–586. doi:10.1146/annurev.genet.42.110807.091714. PMID   18983263.
  15. ↑ Ezaz, Tariq; Quinn, Alexander E.; Miura, Ikuo; Sarre, Stephen D.; Georges, Arthur; Marshall Graves, Jennifer A. (December 2005). "The dragon lizard Pogona vitticeps has ZZ/ZW micro-sex chromosomes". Chromosome Research. 13 (8): 763–776. doi:10.1007/s10577-005-1010-9. ISSN   0967-3849. PMID   16331408. S2CID   4934610.
  16. ↑ "GRAVES, Jennifer Marshall". Australian Honours Search Facility, Dept of Prime Minister & Cabinet. Retrieved 15 March 2018.
  17. ↑ "GRAVES, Jennifer Marshall". Australian Honours Search Facility, Dept of Prime Minister & Cabinet. Retrieved 15 March 2018.
  18. ↑ "2019 NAS Election". National Academy of Sciences. 30 April 2019.
  19. ↑ "Elected Fellows of the Royal Society of Victoria". The Royal Society of Victoria. 22 May 2013. Retrieved 13 October 2023.
  20. ↑ "Australia Day 2022 Honours List". Sydney Morning Herald. Nine Entertainment Co. 25 January 2022. Retrieved 25 January 2022.
  21. ↑ "Decoding dragons and devils, what triggers volcanoes, and more: Australia's stars of science". Australian Academy of Science. 14 March 2023. Retrieved 14 March 2023.
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